Numerical Analysis of the Effect of Shrinkage on Flexural Deformation and Crack Width

Abstract

A numeric and experimental investigation of shrinkage effect on structural concrete members' crack width and short-term and long-term flexural deformation is presented. Solving simultaneous differential equations relating to bond stress-slip relationship-based bond slip was how numerical analysis was performed. There was formulation of equations for an element between two adjacent cracks, taking into consideration fictitious crack model-based tension softening, time dependence of bond, creep, and shrinkage. Present method verification was performed through load tests carried out through 200 mm wide x 205 mm high section structural concrete members made of expansive high strength concrete and conventional high shrinkage concrete, with measurement of curvature and crack width in a constant bending moment zone with 800 mm length. Creep and shrinkage tests were performed in addition to this. The present study resulted in the following conclusions: (1) cracked concrete section tension contributed dominantly to stress reduction in a tension reinforcing bar resulting in flexural stiffness enhancement and in flexural crack width reduction, when tension reinforcing bar stress is below 150 N/mm2 and reinforcing bar ratio is under 1.5%; (2) after sustained loading application, due mainly to tension stiffening loss at cracked section, caused by shrinkage, with time flexural crack widths increase; (3) the present methods explain the above conclusions.